Low Pungency, Long Day Onion

ABSTRACT

The present invention includes long-day onion plants comprising bulbs having low pungency and methods for obtaining such onions. The present invention also provides reagents and materials that can be used in the methods for obtaining such onions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 12/567,035, filed Sep. 25, 2009, which is acontinuation application of U.S. patent application Ser. No. 11/486,083,filed Jul. 14, 2006 (now U.S. Pat. No. 7,671,255, issued Mar. 2, 2010),which claims the benefit of U.S. Provisional Application No. 60/813,625,filed Jul. 15, 2005, each of which is herein incorporated by reference.

FIELD OF THE INVENTION

The present invention includes long day onions having low pungency andmethods for obtaining such onions. The present invention also providesreagents and materials that can be used in the methods for obtainingsuch onions.

BACKGROUND

Onions belong to the lily family, Amaryllidaceae, and the genus, Allium.Alliums comprise a group of perennial herbs having bulbous,onion-scented underground leaves, including such commonly cultivatedcrops as garlic, chives, and shallots. It also includes ornamentalspecies grown for their flowers.

Onions are an important vegetable world-wide, ranking second among allvegetables in economic importance with an estimated value of $6 billiondollars annually. The onion is also one of the oldest cultivatedvegetables in history. The common garden onions are in the speciesAllium cepa. Onions are classified in numerous ways, by basic use,flavor, color, shape of the bulb, and day length. Onions come in white,yellow, and red colors. The bulb may be rounded, flattened, or torpedoshaped.

Commercial onions include “storage onions”, “fresh onions”, “pearl ormini onions”, and “green onions”. “Fresh onions” tend to have a lightercolor with a thin skin, a milder, sweeter flavor, and must be eatenfresh as they do not store well. These onions are available in red,yellow, and white colors, and are often sold under the name of theirregion, e.g., Sweet Imperials, Vidalias, Walla Walla Sweets and TexasSweets. Perhaps the best known of the fresh onions is the Bermuda onion.Fresh onions are available beginning in March or early April and can bepurchased until August.

Storage onions are available from harvest, which is at the beginning ofAugust, and are stored and available throughout the winter months up toabout March. Storage onions have a darker skin that is thicker than thatof a fresh onion. They are also known for intense, pungent flavor,higher percentage of solids and desirable cooking characteristics. Theseonions are also available in red, yellow and white colors. Not all longday length type (long day type) onions are suitable for storage. A truestorage onion is one that can be harvested in late summer or fall, andstored, under proper conditions, until the spring, when the fresh onioncrop is again available.

“Spanish onion”, “Spanish onions”, or “Spanish type” are terms appliedto various long-day onions, generally yellow, though some white, andgenerally varieties that are large and globe-shaped. Spanish onion iscommonly applied to various long day type onions of the type grown inwestern states of the United States (California, Idaho, Oregon,Washington, Colorado) with a bulb size averaging 300-700 grams (g)(typically over 3 inches up to 4 inches but also up to 5 inches indiameter for bulbs classified as “colossal”).

Onion varieties initiate bulbing when both the temperature and a minimumnumber of daylight hours reach certain levels. When onions are firstplanted, they initially develop their vegetative growth, with no sign ofbulb formation until the proper day length for that onion varietytriggers the signal to the plant to stop producing above groundvegetative growth and start forming a bulb. Onions are thus sensitive tothe hours of daylight and darkness they receive, and for most varietiesit is only when the specific combination of daylight and darkness isreached, that the bulb starts to form. Onions are therefore classifiedby the degree of day length that will initiate bulb formation. Onionsare described as short-, intermediate-, and long-day length types. Shortday means that bulbing will initiate at 11 to 12 hours of daylight.Intermediate day is used for onions bulbing at 12 to about 14 hours ofdaylight. Long day onions require about 14 or more hours of daylight forbulb formation to start.

Growers producing onions in more northerly climates plant long-daylength onions. Daylight length varies greatly with latitude, and athigher latitudes long-day onions will produce sufficient top growthbefore the day length triggers bulbing to produce a large bulb. Ashort-day onion grown in the North (higher latitudes) will bulb tooearly and produce relatively small bulbs.

Short day onions are preferred for southern areas such as southernTexas, southern California and Mexico. If a long day type onion isplanted in such a short day climate, it may never experience enough daylength to trigger the bulbing process.

Onions are also classified on flavor, with the common designations ofsweet, mild, and pungent. The flavor of the onion is a result of boththe type of onion and the growing conditions. For instance, soilscontaining a high amount of sulfur result in more pungent flavoredonions. Sweetness in onions is caused by the sugars glucose, fructoseand sucrose. Onions also contain polymers of fructose called fructans.Onion cultivars differ quite markedly in the relative amounts ofsucrose, glucose, fructose and fructans which they contain. They alsodiffer in sugars according to length of storage and location in thebulb. Short day cultivars, which are poor storers, tend to have higherlevels of sucrose, fructose and glucose, but hardly any of the fructans.In contrast, long day type cultivars and intermediate storage cultivarssuch as Pukekohe Longkeeper have less sucrose, glucose and fructose andhigher amounts of fructans.

The fructans do not play a role in sweetness. The balance between levelsof pungency and levels of sugars determines the perception of pungencyin an onion. High levels of pungency can mask high levels of sugars sothat the onion is not perceived as sweet. Onions with low levels ofpungency but low levels of sugars can be perceived as bland. Ideally alow pungency onion would have high levels of sugars and lower levels ofpungency.

It is believed that sunlight strongly influences the development ofpungent flavors. While compounds such as sugars and organic acidscontribute to the flavor of onions, it is a special class ofbiologically active organosulfur compounds which give onions theirdistinctive flavor and aroma. Pungency in onions is caused by thesevolatile sulfur compounds, some of which affect the eyes when onions arefast cut and induce tearing (often called lachrymatory effect). Thereare 3 different flavor precursors in onions: 1-propenyl cysteinesulfoxide, which is usually found in the highest concentration;methyl-cysteine sulfoxide, which is normally found in lesserconcentration; and propyl cysteine sulfoxide, which is found in thelowest concentration.

Storage conditions may also affect pungency, and though the research isconflicting, most studies show an increase in pungency for most long daytype onions during storage. See Shock, C. C., E. B. G. Feibert, and L.D. Saunders. 2004. Pungency of Selected Onion Varieties Before and AfterStorage. Oregon State University, Malheur Experiment Station SpecialReport 1055: 45-46.

Within intact cells the enzyme allinase is compartmentalized in the cellvacuole and the flavor precursors are found in the cytoplasm. Areaction, therefore, only occurs when onion tissues are damaged and theenzyme and substrate are brought together as organelles are disrupted.The kinetics of decomposition are different for each specific flavorprecursor. The decomposition of 1-propenyl cysteine sulfoxide is almostinstantaneous, while the methyl and propyl cysteine sulfoxidedecomposition occurs in several minutes. Primary products produced fromflavor precursor decomposition include pyruvate, ammonia and chemicallyunstable sulfenic acids. Among the sulfenic acids is the lachrymator, ortear producing compound, characteristic of onions. The sulfenic acidsundergo further rearrangement to form thiosulfinates, which areresponsible for the characteristic flavor of onions.

Flavor precursor formation begins with the uptake of sulfate (SO₄ ⁻²) bythe onion, its reduction to sulfide, and subsequent assimilation intocysteine by light-dependent reactions in the leaves of the plant.Glutathione, a tripeptide of cysteine is then synthesized. This thestarting point of the flavor precursor biosynthetic pathway. Thepathways leading to the synthesis of each flavor precursor are not fullyunderstood, although sulfur is known to be transformed through severalidentifiable peptide intermediates, each unique to a specific flavorprecursor.

Researchers have recently developed a tool for documenting differencesamong onion flavor using a laboratory analysis of pyruvic aciddevelopment (PAD). Pyruvic acid has been shown to correlate well withconsumer flavor perception. The PAD measurements are gaining acceptancewithin the industry as a clearer index of onion mildness, even thoughpungency is assessed solely by the amount of enzymatic pyruvic acid. Formost commercial onions, pyruvic acid levels fall between about 1 andabout 18 micromoles per a gram fresh weight. PAD units are given inmicromoles pyruvic acid per gram, fresh weight (μmol/g FW). Short dayonions marketed as low pungency onions will typically have PAD values of5.5 μmol/g FW or less. Onion bulbs having a PAD of 5.5 μmol/g FW or lessare considered sweet according to Vidalia Labs sweet onion certificationspecifications (Shock, C. C., E. B. G. Feibert, and L. D. Saunders.2004. Onion Production from Transplants in the Treasure Valley. OregonState University, Malheur Experiment Station Special Report 1055: 4752).

Long day onions are generally grown in the northern states, because oftheir requirement for long days to initiate bulb production. For thisreason, long day type storage varieties do extremely well in thenorthern states of the United States and Canada, regions that have therequired 14-16 hours of day-length during the summer. There are no longday type onions that have low pungency. Some of the commonly plantedlong day type yellow onion cultivars are Daytona, Ranchero, Granero,Sabroso, Tamara, Hamlet, Fortress, Norstar, Teton, and Vaquero.

Short day varieties do not keep well in storage conditions, and thepungency of short day varieties can climb considerably during storage.Present production in North America and Europe allows harvest of shortday onions from mild winter regions from November through April. Longday onions are available fresh in the late summer and as storage onionsfrom September through March, or even year round, have not beenavailable in low pungency varieties. Sweet onions must be imported fromthe southern hemisphere to fill the gap in sweet onion production(November-February). In the United States, regions like Georgia andTexas produce short day onions from March to June, while low pungencyonions available from November to February are short day onions,produced in the southern hemisphere.

There is a need in the art for the development of onions having lowpungency, particularly, long-day varieties having low pungency. There isalso a need for storage onions in which pungency does not substantiallyincrease during storage.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a long-day onion plantcomprising a bulb having low pungency. In another aspect, the presentinvention provides a Spanish-type onion plant comprising a bulb havinglow pungency.

In one aspect, the present invention provides an onion plant requiringabout 14 or more, or 14 or more contiguous hours of daylight to initiatebulb formation comprising a bulb having low pungency.

In another aspect, the present invention provides a part of an onionplant requiring about 14 or more, or 14 or more contiguous hours ofdaylight to initiate bulb formation, where the plant comprises a bulbhaving a PAD measurement of less than 5.5 μmol/g FW.

In yet a further aspect the present invention provides an onion bulbfrom a onion plant requiring about 14 or more, or 14 or more contiguoushours of light to initiate bulb formation comprising a bulb having a PADmeasurement less than about 5.5 μmol/g FW.

In still another aspect, the present invention provides a container ofonion bulbs from onion plants requiring about 14 or more, or 14 or morecontiguous hours of light to initiate bulb formation comprising bulbshaving an average PAD measurement of less than about 5.5 μmol/g FW.

The present invention also provides a seed of an onion plant requiringabout 14 or more, or 14 or more contiguous hours of light to initiatebulb formation, where the seed is capable of producing an onion planthaving a bulb comprising a PAD measurement of less than about 5.5 μmol/gFW.

In another aspect, the present invention provides a container of seedsof a onion plant requiring about 14 or more, or 14 or more contiguoushours of light to initiate bulb formation where onion bulbs from greaterthan 50% of the seeds are low pungency onions, where a population ofonion bulbs from the seeds have an average PAD measurement of less thanabout 5.5 μmol/g FW pyruvate.

The present invention also provides a method of producing a hybrid onionseed comprising crossing a low pungency onion plant requiring about 14or more or 14 or more hours of light to initiate bulb formation with asecond onion plant, and obtaining F₁ onion seed.

Also provided herein is a seed of WYL 77-5128B, a sample of said seedhaving been deposited under NCIMB Accession No. 41329, as well as onionplants grown therefrom and parts thereof.

The present invention also provides a seed of WYL 77-5168B, a sample ofsaid seed having been deposited under NCIMB Accession No. 41330, as wellas onion plants grown therefrom and parts thereof.

In yet another aspect, the present invention also provides a hybridonion plant having a bulb comprising a PAD measurement of less thanabout 5.5 μmol/g FW, where the onion plant requires about 14 or more, or14 or more contiguous hours of light to initiate bulb formation.

BRIEF DESCRIPTION OF THE DRAWINGS

Various exemplary aspects of this invention will be described in detail,with reference to the following figures, wherein:

FIGS. 1A-1C present a chart showing the results of measurements ofvarious pungency and sweetness levels for a number of commercialvarieties.

DETAILED DESCRIPTION OF THE PREFERRED ASPECTS

The present invention provides a low pungency, long day type onionplant, onion seeds and onion bulbs (onions) produced by the plant,containers of onion bulbs and containers of onion seeds. In one aspect,the onion produces a white, red or yellow onion bulb. In another aspect,the onion produces Spanish type onions.

Onion plants of the present invention are a variety of Allium cepa withimproved traits for flavor, in particular, long day onion plantsproducing long day onion bulbs having low pungency. These and otherfeatures and advantages of this invention are described in, or areapparent from, the following detailed description of various exemplaryaspects of the devices and methods according to this invention.

“Onion”, Allium cepa L. (common onion) is a cool season (tolerant offrost) biennial plant. By “biennial plant” it is meant that Allium cepaL. produces a bulb in the first season and seeds in the second. Onionplants may be grown at any temperature that allows for the growth anddevelopment of the plant. Temperatures that allow for the growth anddevelopment of the onion plants of the present invention include thosebetween about 45° F. and about 95° F. or between about 50° F. and about90° F. Preferable temperatures for growth and development for onionplants of the present invention are between about 55° F. and about 90°F. In another aspect, temperature ranges that allow for seedling growthmay be lower than those for plant growth and development. Temperaturesthat allow for seedling growth include those between about 58° F. andabout 87° F. or between about 63° F. and about 82° F. In a preferredaspect, temperatures for seedling growth are those temperatures betweenabout 68° F. to about 77° F.

By “bulb” or “onion bulb” is meant the commercially harvested, edibleportion of the onion plant. An onion bulb is comprised of concentric,enlarged fleshy leaf bases, also called scales. Onion bulbs may bedeveloping onion bulbs or mature onion bulbs. In a preferred aspect, theonion bulbs of the present invention are mature onion bulbs.

As used herein, a “mature onion bulb” refers to any onion bulb that isready for harvest. Generally, when 25-50% of the onion leaf tops havefallen over, the onion is ready for harvest. At maturity, the outer leafbase preferably dries and becomes scaly as the inner leaf bases thickenand develop into a harvestable bulb.

In one aspect, a long day onion plant of the present invention producesan onion bulb that is low pungency. In another aspect, a long day onionplant of the present invention produces an onion bulb having a PADmeasurement of less than 5.5 μmol/g FW of pyruvate.

Pungency of onion bulbs may be measured using any method for determiningpungency. In one example, pungency is measured by determining thepyruvic acid content of onion bulbs. Pyruvic acid content may beexpressed in any units for expressing pyruvic acid content. In apreferred aspect, pyruvic acid content is expressed in micromoles ofmeasured enzymatic pyruvic acid per gram fresh weight of onion flesh(μmol/g FW). In a preferred aspect, measurements are determined usingthe method for measuring pyruvic acid development (PAD) levels developedby Schwimmer, S.; Weston, W. 1961. Onion Flavor and Odor, EnzymaticDevelopment of Pyruvic Acid in Onions A Measure Of Pungency. Journal OfAgricultural And Food Chemistry 9:301.

In one aspect, low pungency onions of the present invention have PADmeasurements of less than 5.5 μmol/g FW of pyruvate. In another aspect,low pungency onions of the present invention have PAD measurements lessthan 5.0 μmol/g, 4.75 μmol/g, 4.5 μmol/g, 4.25 μmol/g, 4.0 μmol/g, 3.75μmol/g, or 3.5 μmol/g, FW pyruvate. In another aspect, low pungencyonions may have a PAD measurement between about 3.0 μmol/g and about 5.5μmol/g FW pyruvate, between about 4.0 μmol/g and about 5.5 μmol/g FWpyruvate, between about 4.5 μmol/g and about 5.5 μmol/g FW pyruvate, orbetween about 5.0 μmol/g and about 5.5 μmol/g FW pyruvate.

In another aspect, low pungency may also be the result of a reduction inorganosulfur compounds in an onion bulb compared to a reference long dayonion bulb. In one aspect, pungency may be the result of a reduction inorganosulfur compounds including 1-propenyl cysteine sulfoxide,methyl-cysteine sulfoxide, or propyl cysteine sulfoxide compared to areference long day onion. In one aspect, the reference long day onionbulb may be obtained from any commercial long day onion plant. In apreferred aspect, the reference long day onion bulb is a long day onionline, Vision. A reduction in organosulfur compounds may be any reductionin organosulfur compounds. In a preferred aspect, a reduction inorganosulfur compounds is a reduction of at least 10%, 15%, 20%, 25%,30%, 35%, or more of one or more organosulfur compounds compared to aonion bulb from a reference long day onion plant.

In another aspect, pungency may be measured as an average PADmeasurement in a population of onion bulbs. A population of onion bulbsmay have an average PAD measurement of less than about 5.5 μmol/g, lessthan 5.0 μmol/g, less than 4.5 μmol/g, less than 4.0 μmol/g, or lessthan 3.75 μmol/g FW pyruvate. In another aspect, low pungency onions mayhave an average PAD measurement between about 3.0 μmol/g and about 5.5μmol/g FW pyruvate, between about 4.0 μmol/g and about 5.5 μmol/g FWpyruvate, between about 4.5 μmol/g and about 5.5 μmol/g FW pyruvate, orbetween about 5.0 μmol/g and about 5.5 μmol/g FW pyruvate. In oneaspect, a population of onion bulbs may be 5, 10, 15, 20, 25, 30, 35,40, 45, 50, or more onion bulbs.

Average PAD measurements of onion lines, as provided herein, may bedetermined by averaging the PAD measurements of any number of onionbulbs from an onion plant of the present invention. In one example,average PAD measurements are the average of about 5, 10, 15, 20, 25, 30,35, 40, 45, or 50 onion bulbs. In a preferred aspect, the onion plantfrom which the bulb is obtained is a long day onion plant.

An onion attribute such as PAD measurements can be measured at a varietyof times. In one aspect, an attribute is measured following growth in agrowth chamber. In another aspect, an attribute is measured at the timeof harvest. In another aspect, an attribute is measured after storage ofthe onion bulb at ambient conditions for one day, two days, three days,four days, five days, six days, one week, two weeks, three weeks, fourweeks, or five weeks after harvest. In yet another aspect, an attributeis measured after storage of the onion bulb at 5° C. for one day, twodays, three days, four days, five days, six days, one week, two weeks,three weeks, one month, two months, three months, four months, fivemonths, or six months after harvest.

Onion plants may be categorized into three categories according to bulbinitiation in response to various lengths of daylight. In one aspect, a“short day” length type onion plant (short day, or SD, onion) respondsto 11 to 12 hours of daylight for the initiation of bulb formation; an“intermediate day” length type onion plant (intermediate day, or ID,onion) needs 12 to 14 hours of daylight; and a “long day” length typeonion plant (long day, or LD onion) requires about 14 or more contiguoushours of daylight for bulb formation to start. In a preferred aspect,long day onion plants require 14 or more contiguous hours of daylight toinitiate bulb formation.

Daylight length response periods for bulb initiation for a given type ofonion may be expressed in any form, and may be expressed as a number ofcontiguous hours of daylight for any number of days. In one aspect, thehours of daylight are required for at least one day for the onion plantto initiate bulb formation. In another aspect, an onion plant mayrequire 2, 3, 4, 5, 6, 7, 8, 9, 10, or more days of a given number ofcontiguous hours of daylight to initiate bulb formation.

Climate and soils may affect pyruvic acid concentrations. Preferably,low pungency onions should be grown on soils which have a naturally lowsulphur level. High summer temperatures during the growth period mayalso increase pyruvic acid concentrations. When producing low pungencyonions the use of those sowing and harvesting conditions should beobserved that avoid the hottest periods in individual growing regions.Planting density also affects onion pungency. Low plant populations arerecommended for low pungency onions. As used herein, then, “similarfield conditions” refers to appropriate onion growing conditions forpurposes of comparing low pungency lines, i.e., growth in the same fieldand season, in both a region and under conditions appropriate forproducing low pungency onions.

In one aspect, the present invention provides an onion plant requiringabout 14 or more, as well as 14 or more contiguous hours of daylight toinitiate bulb formation comprising a bulb having low pungency.

In another aspect, the present invention provides seed of an onion plantcapable of producing a bulb having a PAD measurement less than about 5.5μmol/g FW of pyruvate. In a preferred aspect, the onion plant grown fromthe seed requires about 14 or more, as well as 14 or more contiguoushours of daylight to initiate bulb formation.

The invention also provides long day onions harvested from a lowpungency, long day onion, for instance, onions harvested from aplurality of low pungency, long day onion plants grown in a field ofonion plants.

The invention further provides a long day onion plant having the traitof producing onion bulbs that are low pungency after storage. In oneaspect, the bulbs preferably remain at a low pungency level at least twomonths of storage, preferably at least about four months under storage,while in further preferred aspects, the onions remain at a low pungencylevel at least about six months under storage. In one preferred aspect,the PAD measurement after two months storage is less than 5.5 μmol/g FWof pyruvate, though in other preferred aspects, the PAD measurementafter two months storage is less than 5.0 μmol/g FW of pyruvate morepreferably, less than 4.5 μmol/g FW of pyruvate, even more preferably,less than about 4.0 or 3.75 μmol/g FW of pyruvate.

In another aspect, onion bulbs of the present invention may be storedunder any conditions suitable for onion bulb storage without asubstantial increase in pungency. In one aspect, storage conditions forlong-term storage of onion bulbs from zero to about six months are undercontrolled climate conditions of about 4 degrees centigrade to about 6degrees centigrade and relative humidity in the range from about 50% toabout 65%. In one aspect, onion bulbs may be stored under suchconditions for at least about 1 month, 2 months, 3 months, 4 months, 5months, or 6 months without a substantial increase in PAD measurement.By “substantial increase” in PAD measurement refers to an increase inPAD measurements by greater than 20% compared to PAD measurementsobtained at the time of harvest. In a preferred aspect, the onion bulbsmay be stored for such periods without an increase of PAD measurement ofmore than 15%, 10%, or 5% compared to the PAD measurement at the time ofharvest.

In one aspect of the invention, mature onion bulbs harvested from theonion plant have a mean PAD measurement after two months storage that isabout equal to or less than the PAD measurement after two months storagefor line WYL 77-5128B, when grown under comparable field conditions.

In another aspect of the invention, onions harvested from the onionplant have a mean PAD measurement after two months storage that is aboutequal to or less than the PAD measurement at harvest for line WYL77-5168B, when grown under comparable field conditions.

For long-term storage, the onion bulbs may be harvested when fullymature and may be allowed to dry in the sun. The bulbs may be turned,particularly after rainy or damp weather, and damaged material rejected.Containers providing air circulation may be used, including such thingsas shallow slatted trays and open mesh sacks. In a preferred aspect,exposure to light is avoided, because light can induce sprouting, andthe onions are kept dry. In a preferred aspect, an onion bulb can bestored for about 1, 2, 3, 4, 5, 6, 7, or 8 months, with losses of lessthan 25%.

In another aspect, a low pungency, long day onion is a long day lengthtype onion plant that will produce low pungency mature onion bulbshaving a PAD value of less than about 5.5 μmol/g FW, when stored for twomonths, four months or six months under long-term storage conditions. Alow pungency, long day onion will also have a PAD value that is equal toor less, when grown under those comparable field conditions, than thePAD values for onions of the long day length line WYL 77-5168B, underlong-term storage conditions for two months, four months or six months.Alternatively, a low pungency, long day onion will have a mean PAD valuethat is equal to or less, when grown under those comparable fieldconditions, than the mean PAD values for onions of the long day lengthline WYL 77-5128B, under long-term storage conditions for two months,four months or six months.

With the present invention, the grower is able to produce a low pungencyonion bulbs that can be grown under long day conditions, and whichstores well. The trait of bulb production under long day conditions andlow pungency line is a great benefit to the grower, as it expands theareas where the desirable low pungency onions may be produced.

Unlike short day onions, the low pungency, long day onions will storefor two months or longer periods under long term storage conditions, andhold their low pungency. In one aspect, the long storage capabilities ofthe low pungency, long day onions, may be used to fill a gap in thepresent production of low pungency onions (November-February). The lowpungency, long day onions may be stored for two months up to six months,or longer, providing a single, continuous source of low pungency onionsfrom growing regions in northern latitudes.

The present invention also provides a container of onion seeds in whichbulbs grown from greater than 50% of the seeds are a low pungency, longday type onion plant. In another aspect, bulbs obtained from onionplants grown from greater than 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%,95% of the onion seeds in the container are low pungency. In one aspect,a population of bulbs obtained from plants grown from the seeds have anaverage PAD content of less than 5.5 μmol/g, 5.0 μmol/g, 4.5 μmol/g, 4.0μmol/g, or 3.75 μmol/g FW of pyruvate. In another aspect, a populationof bulbs obtained from onion plants grown from the seeds have an averagePAD measurement between about 3.75 μmol/g and about 5.5 μmol/g FWpyruvate, between about 4.0 μmol/g and about 5.5 μmol/g FW of pyruvate,between about 4.5 μmol/g and about 5.5 μmol/g FW of pyruvate, or betweenabout 5.0 μmol/g and about 5.5 μmol/g FW of pyruvate. A population ofonion bulbs may contain at least about 10, 15, 20, 25, 30, 35, 40, 45,50, 100, 200, 500, or 1000 or more onion bulbs.

The container of onion seeds may contain any number, weight or volume ofseeds. For example, a container can contain at least, or greater than,about 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000,2500, 3000, 3500, 4000 or more seeds. Alternatively, the container cancontain at least, or greater than, about 1 ounce, 5 ounces, 10, ounces,1 pound, 2 pounds, 3 pounds, 4 pounds, 5 pounds or more seeds.

Containers of onion seeds may be any container available in the art. Byway of non-limiting example, a container may be a box, a bag, a packet,a pouch, a tape roll, or a tube.

In another aspect, the present invention also provides a container ofonion bulbs in which greater than 50% of the bulbs are a low pungencyfrom a long day type onion plant. In another aspect, greater than 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% of the onion bulbs in thecontainer are low pungency. In one aspect, a population of bulbs in thecontainer have an average PAD content of less than 5.5 μmol/g, 5.0μmol/g 4.5 μmol/g, 4.0 μmol/g or 3.75 μmol/g FW of pyruvate. In anotheraspect, a population of bulbs have an average PAD measurement betweenabout 3.75 μmol/g and about 5.5 μmol/g FW pyruvate, between about 4.0μmol/g and about 5.5 μmol/g FW of pyruvate, between about 4.5 μmol/g andabout 5.5 μmol/g FW of pyruvate, or between about 5.0 μmol/g and about5.5 μmol/g FW of pyruvate. A population of onion bulbs may contain atleast about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 100, 200, 500, or1000 or more onion bulbs.

The container of onion bulbs may contain any number, weight or volume ofbulbs. For example, a container can contain at least, or greater than,about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, or 100 bulbs.Alternatively, the container can contain at least, or greater than,about 1 pound, 2 pounds, 3 pounds, 4 pounds, 5 pounds or more of bulbs.

Containers of onion bulbs may be any container available in the art. Byway of non-limiting example, a container may be a box, a flat, a bag, apacket, or a bunch. A container of onion bulbs of the present inventionmay be found in any location, including, but not limited to a warehouse,a distributor, a wholesaler, or a retail market, such as a grocerystore.

The invention further provides a method of producing an onion cropcomprising growing a plurality of low pungency, long day onion plantsand harvesting long day onions from the onion plants. Long day onionsharvested according to this method are also provided.

In one aspect, onion plants of the present invention may be maintainedas open pollinated lines, half-sib lines, or male sterile lines, and mayvary phenotypically with regard to such traits as size, shape, andcolor. In another aspect, the present invention provides inbred onionlines requiring 14 or more hours of contiguous daylight to initiate bulbformation, having low pungency. Male sterile inbreds may be used in theproduction of onion hybrids of the present invention. The development ofonion hybrids in a onion plant breeding program may involve thedevelopment of homozygous inbred lines, the crossing of these lines, andthe evaluation of the crosses. In another aspect of the presentinvention, onion plant breeding programs may combine the geneticbackgrounds from two or more inbred lines or various other germplasmsources into breeding populations from which new inbred lines may bedeveloped by self or sib pollinating and selection of desiredphenotypes. Plant breeding techniques known in the art and used in anonion plant breeding program include, but are not limited to, recurrentselection, backcrossing, double haploids, pedigree breeding, restrictionfragment length polymorphism enhanced selection, genetic marker enhancedselection, and transformation. In one aspect, a combination of thesetechniques may be used. Thus, inbred lines derived from onion plants ofthe present invention may be developed using plant breeding techniquesas described herein. New inbred onion lines may be crossed with otherinbred lines and the hybrids from these crosses may be evaluated todetermine which of those have commercial potential.

Backcrossing methods can be used with the onion plants of the presentinvention to improve or introduce a particular characteristic or set ofcharacteristics into an inbred. The term “backcrossing” as used hereinrefers to the repeated crossing of a hybrid progeny back to one of theparental onion plants for that inbred. The parental onion plant whichcontributes the gene for the desired characteristic is termed thenonrecurrent, or donor, parent. This terminology refers to the fact thatthe nonrecurrent parent is used one time in the backcross protocol andtherefore does not recur. The parental onion plant to which the gene orgenes from the nonrecurrent parent are transferred is known as therecurrent parent, as it is used for several rounds in the backcrossingprotocol. In a typical backcross protocol, the original inbred ofinterest (recurrent parent) is crossed to a second inbred (nonrecurrentparent) that carries the trait or traits of interest to be transferred.The resulting progeny from this cross are then crossed again to therecurrent parent and the process is repeated until an onion plant isobtained wherein essentially all of the desired morphological andphysiological characteristics of the recurrent parent are recovered inthe converted plant, in addition to the one or few transferred traits ofthe nonrecurrent parent. Typically, four or more backcross generationsmay be required, with selection for the desired trait, before theprogeny will contain essentially all genes of the recurrent parentexcept for the genes controlling the desired trait(s). Where molecularmarkers are available for use during the selection process, the programmay be accelerated. The last backcross generation is then selfed to givepure breeding progeny for the gene(s) being transferred.

When the term “inbred”, “inbred plant” or “inbred onion” is used in thecontext of the present invention, this also includes any single geneconversions of that inbred. The term single gene converted plant as usedherein refers to those onion plants which are developed by a plantbreeding technique called backcrossing wherein essentially all of thedesired morphological and physiological characteristics of an inbred arerecovered in addition to the single gene transferred into the inbred viathe backcrossing technique.

Any onion plant can be used in conjunction with the onion plantsdisclosed herein. In a preferred aspect, the source of low pungency isan elite plant. In an aspect, low pungency onions may be produced bybreeding with the following long day sources: Daytona, Ranchero,Granero, Sabroso, Tamara, Hamlet, Fortress, Norstar, Teton, and Vaquero.FIG. 1 provides a chart of measurements of various pungency andsweetness parameters for a number of commercially available (and a fewdevelopmental) long day length onion varieties. As will be apparent, atypical long day type onion coming out of storage during the wintermonths will have a PAD in the 6.2-12 μmol/g FW range, and will be quitepungent. In an aspect, a low pungency onion plant of the presentinvention may be crossed with any inbred onion line having desiredproperties.

As used herein, an “elite line” is any line that has resulted frombreeding and selection for superior agronomic performance. An eliteplant is any plant from an elite line. Plants can be chosen from Spanishonion or other long day germplasm and can be screened for low PADvalues.

Onion plants of the present invention may have been self-pollinated andselected for type over many generations to become homozygous at almostall gene loci and produce a uniform population of true breeding progeny.A cross between two such plants produces a uniform population of hybridplants that are heterozygous for many gene loci. The development ofinbred plants generally requires at least about 2 generations of selfingfollowed by mass selection or sib crossing. Inbred plants may then becross-bred in an attempt to develop improved F₁ hybrids. Hybrids arethen screened and evaluated in small scale field trials. Typically,about 10 to 15 phenotypic traits, selected for their potentialcommercial value, are measured.

The present invention also provides progeny of low pungency onionshaving sufficient genetic material to retain the traits of the onionplants of the present invention. As used herein, the progeny include notonly, without limitation, the products of any cross (be it a backcrossor otherwise) between two plants, but all progeny whose pedigree tracesback to the original cross. In one aspect, without limitation, suchprogeny include plants that have 50%, 25%, 12.5% or less geneticmaterial derived from one of the two originally crossed plants. As usedherein, a second plant is derived from a first plant if the secondplant's pedigree includes the first plant.

Plants generated using a method of the present invention can be part ofor generated from a breeding program. The choice of breeding methoddepends on the mode of plant reproduction, the heritability of thetrait(s) being improved, and the type of cultivar used commercially(e.g., F₁ hybrid cultivar, pureline cultivar, etc). Selected,non-limiting approaches, for breeding the plants of the presentinvention are set forth below. A breeding program can be enhanced usingany method available, such as, marker assisted selection of the progenyof any cross. It is further understood that any commercial andnon-commercial cultivars can be utilized in a breeding program. Factorssuch as, for example, emergence vigor, vegetative vigor, stresstolerance, disease resistance, flowering, seed set, seed size, seeddensity, standability, and bulb size will generally dictate the choice.

The present invention provides processes of preparing novel onion plantsand onion plants produced by such processes. In accordance with such aprocess, a first parent onion plant may be crossed with a second parentonion plant wherein at least one of the first and second onion plants isan inbred low pungency, long day onion plant as described herein. Oneapplication of the process is in the production of F₁ hybrid plants.Another important aspect of this process is that it can be used for thedevelopment of novel inbred lines. For example, an inbred low pungencyonion plant as described herein could be crossed to any second plant,and the resulting hybrid progeny each selfed or sib-pollinated for about2 or more generations, thereby providing a large number of distinct,pure-breeding inbred lines. These inbred lines could then be crossedwith other inbred or non-inbred lines and the resulting hybrid progenyanalyzed for beneficial characteristics. In this way, novel inbred linesconferring desirable characteristics could be identified.

Onion plants of the present invention can be crossed by either naturaltechniques, such as through insect pollination. In one aspect, crossingcomprises the steps of:

-   -   (a) planting in pollinating proximity seeds or bulbs of a first        and a second parent onion plant, and preferably, seeds or bulbs        of a first inbred onion plant and a second, distinct inbred        onion plant;    -   (b) cultivating or growing the seeds or bulbs of the first and        second parent onion plants into plants that bear flowers;    -   (c) allowing natural cross-pollination to occur between the        first and second parent onion plants;    -   (d) harvesting seeds produced on the parent onion plants; and,        where desired,    -   (e) growing the harvested seed into an onion plant, preferably,        a hybrid onion plant.

Parental plants may be planted in pollinating proximity to each other byplanting the parental plants in alternating rows, in blocks, in breedingcages or in any other convenient planting pattern. Where the parentalplants differ in timing of sexual maturity, it may be desired to plantthe slower maturing plant first, thereby ensuring the availability ofpollen from the male parent during the time at which the female parentare receptive to pollen. Plants of both parental parents are cultivatedand allowed to grow until the time of flowering. Advantageously, duringthis growth stage, plants are in general treated with fertilizer and/orother agricultural chemicals as considered appropriate by the grower.

Alternatively, in another aspect of the invention, both first and secondparent onion plants can be a low pungency, long day onion plant asdescribed herein. Thus, any onion plant produced using a low pungency,long day onion plant as described herein forms a part of the invention.As used herein, crossing can mean selfing, sib-crossing, backcrossing,crossing to another or the same inbred, crossing to populations, and thelike. All onion plants produced using a low pungency, long day onionplant as described herein as a parent are, therefore, within the scopeof this invention.

A further aspect of the present invention relates to tissue cultures ofthe onion plants described herein. As used herein, the term “tissueculture” indicates a composition comprising isolated cells of the sameor a different type or a collection of such cells organized into partsof a plant. Exemplary types of tissue cultures are protoplasts, calliand plant cells that are intact in plants or parts of plants, such asembryo, leaf, peduncle, pedicel, anther, meristem, bulb, stump and stem,explants, and the like. In a preferred aspect, the tissue culturecomprises embryos, protoplasts, meristematic cells, pollen, leaves oranthers derived from immature tissues of these plant parts. Means forpreparing and maintaining plant tissue cultures are well known in theart.

Seed of the inbred long day onion (Allium cepa) plants designated WYL77-5128B have been deposited at the National Collections of Industrialand Marine Bacteria (NCIMB Limited, Ferguson Building, CraibstoneEstate, Bucksburn, Aberdeen, Scotland; AB21 9YA, UK) as accession No.41329. Seed of the inbred long day onion plants designated WYL 77-5168Bhave similarly been deposited at NCIMB, as accession No. 41330. Theseed, plants grown from the seed, and seed derived from such plants, arealso provided herein.

In a further aspect of the invention, seed is provided for a long dayonion plant having as at least one parent a plant grown from seed of anyone of long day onion plants WYL 77-5128B and WYL 77-5168B. The plantmay be a hybrid plant having one or both parents selected from the longday onion plants WYL 77-5128B and WYL 77-5168B. The invention furtherprovides a long day onion plant, or parts thereof, produced by growingseed of such a long day onion plant.

The invention also provides long day onions harvested from a long dayonion plant grown from the long day onion plant produced from such seedor by any means of asexual reproduction.

The invention also provides long day onion plants having thephysiological and morphological characteristics of the long day onionplants WYL 77-5128B and WYL 77-5168B. The invention contemplates plantsor plant products produced from protoplasts or regenerable cells fromthe long day onion plants, using tissue culture where the cells orprotoplasts are produced from a plant tissue selected from the groupconsisting of leaf, pollen, cotyledon, hypocotyl, embryos, root, pod,flower, shoot and stem.

Another aspect of the invention provides low pungency, long day onionplants or parts thereof, where the plant or parts thereof have beentransformed to contain one or more transgenes operably linked toregulatory elements functional in the long day onion plant.

A still further aspect of the invention provides pollen or an ovule ofWYL 77-5128B and WYL 77-5168B, or an onion tissue culture derived fromcells of such long day onion plants, particularly a long day onion plantregenerated from such tissue culture and having the trait of being lowpungency, long day length.

Use of onion plants or any parts thereof of the invention, such as forbreeding purposes, is also provided by the invention. More particularly,a method is contemplated whereby an F₁ onion plant is grown from F₁ seedresulting from a cross of a long day, low pungency onion plant of theinvention as at least one parent onion plant, and selecting progenyonion plants having desired traits. In a further preferred aspect, twoor more generations of back crossing to one of the parent onion plantsis used in breeding a new line of long day, low pungency onion plant.

WYL 77-5168B is a long day Spanish onion breeding line, combining allthe desired features of typical long day Spanish onions with theadditional feature of low pungency. The variety that most closelyresembles is WYL 77-5168B is Vision. The comparative characteristic thatmost readily distinguishes the low pungency varieties such asWYL77-5168B from all other long day varieties is the unique low pungency(“mildness”) of WYL 77-5168B. This level of low pungency is unique foronions that respond to photoperiod under long day conditions to inducebulbing.

Seed from Allium cepa breeding line WYL 77-5168B, described above, wasdeposited on 24 Jun. 2005 with NCIMB Ltd., as Accession No. NCIMB 41330Allium cepa WYL 77-5168B.

WYL 77-5128B is long day Spanish onion breeding line, combining all thedesired features of typical long day Spanish onions with the additionalfeature of low pungency. Again, the variety that most closely resemblesWYL 77-5128B is Vision. WYL 77-5128B produces a low pungency onion underphotoperiods of long day conditions to induce bulbing. Seed from Alliumcepa breeding line WYL 77-5128B, described above, was deposited on 24Jun. 2005 with NCIMB Ltd., as Accession No. NCIMB 41329 Allium cepa WYL77-5128B.

In a preferred aspect, the long day, low pungency onion plants of thepresent invention may be used in the production of hybrid seed. Any timea low pungency onion plant as described herein is crossed with another,different, onion inbred, a first generation (F₁) onion hybrid plant isproduced. As such, an F₁ hybrid onion plant can be produced by crossinga low pungency onion plant, for example, as described herein with anysecond inbred onion plant. Essentially any other onion plant can be usedto produce a hybrid onion plant having a long day, low pungency onionplant as described herein as one parent. All that is required is thatthe second plant be fertile, which onion plants naturally are.

Onion has a diploid phase which means two conditions of a gene (twoalleles) occupy each locus (position on a chromosome). If the allelesare the same at a locus, there is said to be homozygosity. If they aredifferent, there is said to be heterozygosity. Because many loci whenhomozygous are deleterious to the plant, in particular leading toreduced vigor, poor bulb quality, weak and/or poor growth, production ofinbred plants is an unpredictable and arduous process. Under someconditions, heterozygous advantage at some loci effectively barsperpetuation of homozygosity.

A single cross hybrid onion variety is the cross of two inbred plants,each of which has a genotype which complements the genotype of theother. Typically, F₁ hybrids are more vigorous than their inbredparents. This hybrid vigor, or heterosis, is manifested in manypolygenic traits, including markedly improved yields, better roots,better uniformity and better insect and disease resistance. In thedevelopment of hybrids only the F₁ hybrid plants are typically sought.An F₁ single cross hybrid is produced when two inbred plants arecrossed. A three way cross hybrid is produced from three inbred plantscrossed initially between two inbreds (A×B) and then crossing the F₁hybrid with a third inbred line (A×B)×C.

Any of the onion varieties known to those of skill in the art can becrossed with a long day, low pungency onion line of the presentinvention to produce a hybrid plant.

When an inbred low pungency onion plant as described herein is crossedwith another inbred plant to yield a hybrid, it can serve as either thematernal or paternal plant. For many crosses, the outcome is the sameregardless of the assigned sex of the parental plants. Depending on theseed production characteristics relative to a second parent in a hybridcross, it may be desired to use one of the parental plants as the maleor female parent. Therefore, a decision to use one parent plant as amale or female may be made based on any such characteristics as is wellknown to those of skill in the art.

The development of new varieties using one or more starting varieties iswell known in the art. In accordance with the invention, novel varietiesmay be created by crossing an inbred long day, low pungency onion plantas described herein followed by multiple generations of breedingaccording to such well known methods. New varieties may be created bycrossing a long day, low pungency onion plant as described herein withany second plant. In selecting such a second plant to cross for thepurpose of developing novel inbred lines, it may be desired to choosethose plants which either themselves exhibit one or more selecteddesirable characteristics or which exhibit the desired characteristic(s)when in hybrid combination. Examples of potentially desiredcharacteristics include greater yield, resistance to insecticides,herbicides, pests, and disease, tolerance to heat and drought, reducedtime to crop maturity, better agronomic quality, higher nutritionalvalue, and uniformity in germination times, growth rate, maturity, andbulb size.

Once initial crosses have been made with a long day, low pungency onionplant of the present invention, inbreeding takes place to produce newinbred varieties. Inbreeding requires manipulation by human breeders.Even in the extremely unlikely event inbreeding rather thancrossbreeding occurred in natural onion, achievement of completeinbreeding cannot be expected in nature due to well known deleteriouseffects of homozygosity and the large number of generations the plantwould have to breed in isolation. The reason for the breeder to createinbred plants is to have a known reservoir of genes whose gametictransmission is predictable.

The pedigree breeding method involves crossing two genotypes. Eachgenotype can have one or more desirable characteristics lacking in theother; or, each genotype can complement the other. If the two originalparental genotypes do not provide all of the desired characteristics,other genotypes can be included in the breeding population. Superiorplants that are the products of these crosses are selfed or sib-crossedand selected in successive generations. Each succeeding generationbecomes more homogeneous as a result of self-pollination and selection.Typically, this method of breeding involves one or two generations ofselfing or sib-crossing followed by mass selection or sibbing: S₁→S₂;S₂→S₃. After at least five generations, the inbred plant is consideredgenetically pure. The onion plants of the present invention may begenetically pure or S₁, S₂, S₃, etc.

Many traits have been identified that are not regularly selected for inthe development of a new variety but that can be improved bybackcrossing techniques. A genetic locus conferring the traits may ormay not be transgenic. Examples of such traits known to those of skillin the art include, but are not limited to, male sterility, herbicideresistance, resistance for bacterial, fungal, or viral disease, insectresistance, male fertility and enhanced nutritional quality. These genesare generally inherited through the nucleus, but may be inheritedthrough the cytoplasm. Some known exceptions to this are genes for malesterility, some of which are inherited cytoplasmically, but still act asa single locus trait.

Direct selection may be applied where a genetic locus acts as a dominanttrait. An example of a dominant trait is the herbicide resistance trait.For this selection process, the progeny of the initial cross are sprayedwith the herbicide prior to the backcrossing. The spraying eliminatesany plants which do not have the desired herbicide resistancecharacteristic, and only those plants which have the herbicideresistance gene are used in the subsequent backcross. This process isthen repeated for all additional backcross generations.

Many useful traits are those which are introduced by genetictransformation techniques. Methods for the genetic transformation ofonion are known to those of skill in the art. For example, methods whichhave been described for the genetic transformation of onion may includeelectroporation, electrotransformation, microprojectile bombardment,Agrobacterium-mediated transformation, direct DNA uptake transformationof protoplasts and silicon carbide fiber-mediated transformation. See,e.g., Khachatourians, G., et al., eds., Transgenic Plants and Crops,Marcel Dekker, Inc. (2002).

It is understood to those of skill in the art that a transgene need notbe directly transformed into a plant, as techniques for the productionof stably transformed onion plants that pass single loci to progeny byMendelian inheritance is well known in the art. Such loci may thereforebe passed from parent plant to progeny plants by standard plant breedingtechniques that are well known in the art. Examples of traits that maybe introduced into an onion plant according to the invention include,for example, male sterility, herbicide resistance, disease resistance,insect resistance, and enhanced nutritional quality.

PCR and Southern hybridization are two examples of molecular techniquesthat can be used for confirmation of the presence of a given locus andthus conversion of that locus.

Every reference, patent, or other published work cited above is hereinincorporated by reference in its entirety.

EXAMPLES

WYL 77-5128B and WYL 77-5168B are long day onions producing bulbs underlong day conditions. Various field trials were conducted with breedinglines in selecting low pungency, long day onions, comparing the lowpungency, long day onions with control long day onions, includingVision, grown under comparable field conditions. Vision is a CMS hybridpresently marketed by Seminis, a hybrid yellow Spanish type onion oflong day class, with full season maturity and excellent storage.

Collected onion samples were analyzed for pyruvate (PAD levels),according to the methods described (Schwimmer, S.; Weston, W. 1961.Onion Flavor and Odor, Enzymatic Development of Pyruvic Acid in Onions AMeasure Of Pungency. Journal Of Agricultural And Food Chemistry 9:301).

As is true with other onion cultivars, a small percentage of variantscan occur within commercially acceptable limits for almost anycharacteristics during the course of onion multiplication. No variantswere observed during the years in which WYL 77-5128B and WYL 77-5168Bwere observed to be uniform and stable.

Example 1: WYL 77-5168B Long Day Onion

WYL 77-5168B, a long day onion inbred, was developed by mass selectionfrom a synthetic gene pool of Yellow Sweet Spanish onion (synthetic genepool YSS-715B). Mass selection is the formation of a compositepopulation through selective harvest of individuals among a heterozygouspopulation. See, Burton, G. W. 1990. Enhancing germplasm with massselection. p. 99-100. In: J. Janick and J. E. Simon (eds.), Advances innew crops. Timber Press, Portland, Oreg.

Synthetic gene pool YSS-715B was developed from a pool of YSS 53-351 B(50%), and YSS 805 (50%). This pool was created for other phenotypicpurposes, with no initial interest with regard to pungency.

WYL 77-5168B is a Spanish onion line that is large in size, with a roundbulb shape and medium colored skin. Tops are medium and somewhat floppy.Storage length of WYL 77-5168B is medium term. Maturity of WYL 77-5168Bis full-season for a Spanish type onion.

Year 1 Mass 1 generation bulbs were selected from synthetic YSS-715B.

Year 2 Seed was produced on the M1 bulb selection.

Year 3 Mass 2 generation bulbs were selected from 1995 seed production.

Year 4 Seed was produced in cage 97-575 from the 1996 M2 bulb selection.

Year 5 Mass 3 generation bulbs were selected from source 97-575.

Year 6 Seed was produced from M3 bulb selections in cage 99-327-1.Additional bulbs were also grown of source 97-575 in row number 99-7099and bulb selections were made.

Year 7 Mass 4 generation seed was produced in cage 00333-1 from bulbsgrown in row number 99-7099.

Year 8 Bulbs were grown in row 01OS3164 from original seed source00333-1 and parent breeding line WYL 77-5168B was assigned. WYL 77-5168Bshowed good characteristics for size, skin retention and lack of bolters(seed-stem formation, or “bolting”, produces poor quality bulbs with ahard center making them unmarketable). This line also producedsufficient seed for further development. In the initial screen, WYL77-5168B had a mean PAD of 4.53 μmol/g FW. WYL 77-5128B had a mean PADof 6.48 μmol/g FW. Three other lines, less favorable for other traits,had mean PADs of 5.82, 6.16 and 6.22 μmol/g FW. Of the remaining linestested, there were ten between 6.5 and 7.0, twenty-one between 7.0 and7.5, eleven between 7.5 and 8.0, fourteen between 8.0 and 8.5, fourteenbetween 8.5 and 9.0, ten between 9.0 and 9.5, three between 9.5 and10.0, eight between 10.0 and 10.5, and five greater than 10.5. The lowPADS for certain of the lines led to selection for those lines insubsequent generations based on mean PAD levels after two months storageunder long term storage conditions.

Year 9 Mass 5 generation seed was produced in cage RNG4005 from bulbsgrown in row number 0IOS3164. Additional bulbs were grown in row02053097 from seed source 00333-1. Pungency testing on these bulbsshowed line WYL 77-5168B having pungency level of 4.53 μmol/g FW PAD(min 2.14, max 6.98) after two months of storage.

Year 10 Seed Production Cycle—Mass 5 generation seed was produced incages RNR5613, RNR5616, RNR5617, RNR5619 from bulbs grown in row number02053097 from original source 00333-1 (M-4). Pungency testing on thesebulbs showed line WYL 77-5168B having a pungency level of 4.51 PAD (min2.30, max 9.97) after six months of storage. Cage RNR5619 was a lowpungency selection with a mean of 3.91 PAD (min 2.56, max 4.96).

Year 10 Bulb Production Cycle—Bulbs of WYL 77-5168B were grown in bulbrow 03054045 from original seed source 00333-1. Pungency testing on bulbrow 03054045 showed line WYL 77-5168B having a mean pungency of 5.16 PAD(thin 1.82, max 11.94) after six months of storage. Vision was grown inrows 030S 1283 and 030S 1317 and pooled for analysis and had a meanpungency level of 9.15 PAD (min 6.25, max 15.44) after six months ofstorage.

Year 11 Seed Production Cycle—Seed was produced of line WYL 77-5168B incage RNV4012 from original seed source 00333-1. RNV4012 was a lowpungency selection with—a mean level of 3.74 PAD (min 1.82, max 4.57).

Year 11 Bulb Production Cycle—The bulbs of WYL 77-5168B from an originalsource 00333-01 were tested after two months of storage and showed amean pungency level of 6.02 PAD (min 4.28, max 8.19). An advancedselection of WYL 77-5168B, RNR5616-2 was grown in row 04OS7076 showed amean pungency level of 4.09 PAD (min 3.52, max 5.75) after two months ofstorage. An advanced selection of WYL 77-5168B, RNR5616-12 was grown inrow 04OS7085 showed a mean pungency level of 4.87 PAD (min 3.80, max7.45) after two months of storage. An advanced selection of WYL77-5168B, RNR5616-7 was grown in row 04OS7081 showed a mean pungencylevel of 5.09 PAD (min 3.68, max 6.75) after two months of storage. Anadvanced selection of WYL 77-5168B grown in row 04OS7086, RNR5616-15showed a mean pungency level of 5.15 PAD (min 3.86, max 6.08) after twomonths of storage. An advanced selection of WYL 77-5168B, RNR5616-3 wasgrown in row 04OS7077 showed a mean pungency level of 5.30 PAD (min3.70, max 5.75) after two months of storage. Vision was also analyzedand from replication 1 showed a mean pungency level of 6.07 PAD (min4.94, max 7.24) and from replication 2 showed a mean pungency level of6.25 (min 5.14, max 7.40). Peruvian Sweets (Bland Farms source), shortday type (SD) onions imported and purchased for this study, showed amean pyruvate level of 6.04 PAD (min 4.67, max 7.94).

Selection criteria in the field represent a balance of characteristicsrelated to productivity and fit to the market including, yieldpotential, foliage, bulb shape, bulb skin, bolting tolerance, longstorage, and resistance to pink root and fusarium.

Observations in Year 8, Year 9, Year 10, and Year 11 confirm thatbreeding line WYL 77-5168B is uniform and stable within commerciallyacceptable limits.

Example 2: WYL 77-5128B. Long, Day Onion

WYL 77-5128B, a long day Spanish onion inbred, was developed by massselection from a synthetic gene pool of Yellow Sweet Spanish (syntheticgene pool YSS-FR713B).

Synthetic gene pool YSS-FR713B was developed from a pool of YSS-Giano(50%), YSS 53-351B (25%), and YSS Peckham (25%).

WYL 77-5128B is a low pungency Spanish onion line, that is medium insize, with a high globe shape and dark colored skin. Tops are large andupright. Storage length of WYL 77-5128B is long term. Maturity of WYL77-5128B is mid season for a Spanish type onion

Year 1 Mass 1 generation bulbs were selected from synthetic YSS-FR713B.

Year 2 Seed was produced on the M1 bulb selection.

Year 3 Mass 2 generation bulbs were selected from 1996 seed production.

Year 4 Seed was produced in cage 97-547 from the 1996 M2 bulb selection.

Year 5 Mass 3 generation bulbs were selected from source 97-547.

Year 6 Seed was produced from M3 bulb selections in cage 00335-1.

Year 7 Mass 4 generation bulbs were selected in row O1OS3182 (fromoriginal seed source 00335-1) and parent breeding line WYL 77-5128B wasassigned. As noted above, selections from this point forward werescreened for mean PAD levels after two months storage under long termstorage conditions.

Year 8 Seed was produced from 01OS3182 bulb production in cages RNG3243and RNG3968 (M4 seed). Bulbs were grown in row 02OS3029 from originalseed source 00335-1 Pungency testing on these bulbs showed line WYL77-5128B having pungency level of 5.40 PAD (min 3.41, max 8.23) aftertwo months of storage.

Year 9 Seed production of Mass 4 generation seed was produced in cageRNR5724 and RNR5621 from bulbs grown in row number 02OS3029. CageRNR5621 was a low pungency selection with a mean of 4.72 (min 3.41, max5.58).

Year 9 Bulb production Cycle—Bulbs were grown in row 03OS4043 from seedsource 00335-1. Pungency testing on bulb row 03OS4043 showed lineWYL77-5128B having a mean pungency of 7.87 PAD (min 4.38, max 11.93)after six months of storage. Vision was grown in rows 030S1283 and030S1317 and pooled for analysis and had a mean pungency level of 9.15PAD (min 6.25, max 15.44) after six months of storage. This trialreceived hail damage and did not develop normal size, resulting insmaller more pungent bulbs.

Year 10 Seed was produced of line WYL 77-5128B in cage RNV4014 from seedsource 00335-1. RNV4014 was a low pungency selection with a mean levelof 5.96 PAD (min 4.38, max 6.50).

Year 10 Bulb production cycle—The bulbs of selection WYL 77-5128B fromoriginal seed source 00335-1 were tested after two months of storage andshowed a mean pungency level of 5.32 PAD (min 3.24, max 6.95). Anadvanced selection of WYL 77-5128B, RNR5621-13 was grown in row 04OS7097showed a mean pungency level of 4.29 PAD (min 3.12, max 5.60) after twomonths of storage. An advanced selection of WYL 77-5128B, RNR5621-15 wasgrown in row 04OS7099 showed a mean pungency level of 4.37 PAD (min3.40, max 5.59) after two months of storage. An advanced selection ofWYL 77-5128B, RNR5621-5 was grown in row 04OS7090 showed a mean pungencylevel of 4.53 PAD (min 3.32, max 6.20) after two months of storage. Anadvanced selection of WYL 77-5128B, RNR5621-8 was grown in row 04OS7093showed a mean pungency level of 4.67 PAD (min 3.26, max 5.60) after twomonths of storage. An advanced selection of WYL 77-5128B, RNR5621-12 wasgrown in row 04OS7096 showed a mean pungency level of 4.81 PAD (min3.88, max 6.49) after two months of storage. An advanced selection ofWYL 77-5128B, RNR5621-10 was grown in row 04OS7095 showed a meanpungency level of 4.87 PAD (min 3.94, max 5.75) after two months ofstorage. An advanced selection of WYL 77-5128B, RNR5621-3 was grown inrow 04OS7089 showed a mean pungency level of 5.03 PAD (min 3.82, max6.01) after two months of storage. An advanced selection of WYL77-5128B, RNR5621 was grown in row 04OS7009 showed a mean pungency levelof 5.10 PAD (min 3.65, max 8.79) after two months of storage. Vision wasalso analyzed and from replication 1 showed a mean pungency level of6.07 PAD (min 4.94, max 7.24) and from replication 2 showed a meanpungency level of 6.25 (min 5.14, max 7.40). Peruvian Sweets (BlandFarms source), SD onions imported and purchased for this study, showed amean pyruvate level of 6.04 PAD (min 4.67, max 7.94).

Selection criteria in the field represent a balance of characteristicsrelated to productivity and fit to the market including, yieldpotential, foliage, bulb shape, bulb skin, bolting tolerance, longstorage, and resistance to pink root and fusarium.

Example 3: Pungency in Storage

Harvested low pungency long day onions were stored under storageconditions of 5 degrees centigrade and 50% relative humidity for 6months.

Tables 1 and 2 below provide raw data for mean PAD measurements aftertwo and six months storage under long term storage conditions on thelines noted above.

TABLE 1 History of pungency selection of line WYL 77-5168B Mean PAD Year9 Year 10 Year 11 Year 12 Source Bulb Harvest Bulb Harvest Bulb HarvestBulb Harvest 00333-1 4.53 g FW (2) 4.51 g FW (2) (3) 6.02 g FW (1) 4.70g FW (1) (original 4.20 g FW (2) 3.90 g FW (2) source) RNR5619 5.60 g FW(1) (selection of 4.16 g FW (2) 00333-1) RNR5616-2 4.09 g FW (1)(selection of 4.98 g FW (2) 00333-1) RNR5616-3 5.30 g FW (1) (selectionof 4.24 g FW (2) 00333-1) RNR 5616-7 5.09 g FW (1) (selection of 4.12 gFW (2) 00333-1) RNR 5616-12 4.87 g FW (1) (selection of 4.91 g FW (2)00333-1) RNR 5616-15 5.15 g FW (1) (selection of 3.28 g FW (2) 00333-1)Vidalia Sweets 9.15 g FW (4) 3.34 g FW (4) 3.20 g FW (4) (SD) Vision9.15 g FW (3) 6.16 g FW (1) 5.50 g FW (1) (long day 8.71 g FW (2) 7.35 gFW (2) Spanish Variety) TX 1015Y 4.69 g FW (4) (SD control variety)Peruvian 6.02 g FW (4)  4.3 g FW (4) Sweet (SD) (1) After two monthsstorage (2) After six months storage (3) Field received damage from ahail storm prior to harvest, which reduced size and stopped normalmaturity. (4) Locally purchased source

TABLE 2 History of pungency selection of line WYL 77-5128B Mean PAD Year8 Source Bulb Year 9 Year 10 Year 11 Bulb Harvest Harvest Bulb HarvestBulb Harvest Bulb Harvest 00335-1 5.40 g FW (2) 7.87 g FW (2) (3) 5.32 gFW (1) 4.70 g FW (1) (original source) 6.30 g FW (2) 6.40 g FW (2) RNR5621 5.10 g FW (1) (selection of 6.21 g FW (2) 00335-1) RNR 5621-3 5.06g FW (1) (selection of 5.84 g FW (2) 00335-1) RNR 5621-5 4.53 g FW (1)(selection of 6.35 g FW (2) 00335-1) RNR 5621-8 4.67 g FW (1) (selectionof 6.01 g FW (2) 00335-1) RNR 5621-10 4.87 g FW (1) (selection of 5.75 gFW (2) 00335-1) RNR 5621-12 4.81 g FW (1) (selection of 6.00 g FW (2)00335-1) RNR 5621-13 4.29 g FW (1) (selection of 5.99 g FW (2) 00335-1)RNR5621-15 4.37 g FW (1) (selection of 5.90 g FW (2) 00335-1) VidaliaSweets 9.15 g FW (4) 3.34 g FW (4) 3.20 g FW (4) (SD) Vision 9.15 g FW(3) 6.16 g FW (1) 5.50 g FW (1) (long day Spanish 8.71 g FW (2) 7.35 gFW (2) Variety) TX 1015Y 4.69 g FW (4) 4.69 g FW (4) (SD controlvariety) Peruvian Sweet 6.02 g FW (4) 4.30 g FW (4) (SD) (1) After twomonths storage (2) After six months storage (3) Field received damagefrom a hail storm prior to harvest, which reduced size and stoppednormal maturity and made much smaller bulbs. (4) Locally purchasedsource

Example 4: Long Day Length Types Storage Onions

Long day length type, low pungency onions were stored under storageconditions of 5 degrees centigrade and 50% relative humidity for 6months and evaluated far marketable yield. Marketable yield, sometimescalled “storability”, refers to the retention of onion quality at a highlevel. Quality is assessed by monitoring internal sprout development, aswell as the presence of surface mold and decay.

Table 3 provides data for storability, as percentage marketable bulbsremaining after six months storage under long term storage conditions.The B line designation refers to a more advanced line, having completedseveral generations of selection.

TABLE 3 Storage Characteristics of WYL 77-5128B and WYL 77-5168B %marketable bulbs Storage Storage Storage % Storage % % Storage % % after2 after 3 after 4 after 5 after 6 months months months months months WYL77-5128B 98.8% 97.6% 96.4% 96.4% 95.2% (long day type) WYL 77-5168B98.7% 97.4% 97.4%   82% 74.3% (long day type) Vision 100.0% 98.6% 93.1%93.1% 87.7% (long day type) Peruvian Sweets 79.7% 72.4% 53.6% 37.7%11.6% (SD type)

The results in Table 3 demonstrate that the long day, low pungencyonions provide excellent storage up to 6 months.

Example 5: WYL 77-5126B. Long, Day Onion

WYL 77-5126B, a long day onion inbred, was developed by selfing and massselection from a synthetic gene pool of Yellow Sweet Spanish onion(synthetic gene pool YSS-7171-5B).

In Year 1, seed was produced on a single bulb (self) of syntheticYSS7171-5B seed cage lot 95-183 selfing cage.

In year 2 bulbs were grown from the year 1 self in row Yr2-7156.

In year 3, seed was grown on a mass selection of bulbs from bulb rowYr2-7156 in cage 97-311-1.

In year 4, bulbs were grown from seed source 97-311-1 in bulb row99-7102.

In year 5, seed was grown from bulb row 99-7102 in cage 00611-1C

In year 6, bulbs were grown in bulb row 01OS3170 from cage 00611-1C.Bulbs were found to be uniform and parent breeding line WYL 77-5126B wasassigned. Pungency testing on these bulbs showed line WYL 77-5126Bhaving a pungency level of 5.82 PAD after six months storage.

In year 10, bulbs were grown in bulb row 05OS3118 from seed source00611-1C. Pungency testing two months after storage showed line WYL77-5126B have a pungency level of 6.3 PAD. After six months storage, WYL77-5126B had a 5.62 PAD.

In year 11, seed was grown from bulb row 05OS3118 in cage RND1687. Amass selection of WYL77-5126B with a 3.67 PAD was made.

Example 6: WYL 77-5391B. Long, Day Onion

WYL 77-5391B, a long day onion inbred, was developed by half-sibselection and mass selection from a Yellow Sweet Spanish onion parent(WYL77-5168B).

In Year 1, bulbs were grown of source parent WYL77-5168B in bulb row02OS3097.

In Year 2, a mass selection of WYL 77-5168B was made in cage RNR5616. Asingle plant of this mass selection was designated RNR5616-2 and seedfrom this plant was harvested as a single plant (a half-sib selection).

In Year 4, bulbs were grown in bulb row 05OS7001 from seed sourceRNR5616-2. Bulbs were found to be uniform and parent line WYL 77-5391Bwas assigned. Pungency testing two months after storage showed line WYL77-5391B have a pungency level of 4.4 PAD. After six months storage, WYL77-5391B had a 3.99 PAD.

In Year 6 seed was grown from bulb row 05OS7001 in cage RND1698. A massselection of WYL77-5391B with a 3.17 PAD was made.

Example 7: WYL 77-5392B. Long, Day Onion

WYL 77-5392B, a long day onion inbred, was developed by mass selectionfrom a Yellow Sweet Spanish onion parent (WYL77-5168B).

In Year 1, bulbs were grown of source parent WYL77-5168B in bulb row05OS3152. Pungency testing of line WYL77-5168B after two months storagehad a 4.7 PAD.

In Year 2 mass selection of WYL 77-5168B was made in cage RND1699. Aftersix months storage this mass selection was found to have a 3.34 PAD.This mass selection was designated WYL 77-5392B, having a significantlower PAD than the original parent source.

Example 8: Plant Breeding and Line Development

Various Allium cepa lines of this invention can be used to transmit thelong day photoperiodic response, low pungency trait to new varietiesusing various cross pollination and selection methods. Therefore,breeders may obtain hybrids using the described low pungency, long dayonion plants and lines for further selfing and subsequent selection.Using standard crossing, backcrossing and selection techniques, those ofskill in the art may obtain commercial low pungency, long day onionswith various desirable traits besides those described above. Forexample, breeders may easily obtain commercial Allium cepa lines withthe preferred trait of long day onion color, disease resistance traits,traits relating to optimized yield under specific growth conditions

Example 9: Onion Production

Onions are usually planted in multiple rows on beds. Beds are commonlyformed at or just before planting with 2 to 12 rows planted per bed. Atypical arrangement is two double rows spaced about 12 inches apart on34- or 44-inch beds. Multiple such arrangements are sometimes used,particularly with drip irrigation systems. Some low pungency onions areplanted in single rows.

Onion seed is expensive, and is generally direct seeded with precisionplanters (onions are not thinned). Seed is commonly planted about ¼- to½-inch deep. With furrow irrigation in lighter textured soils or withlimited soil moisture, a depth of ¾ inch may be required.

Hybrid seed of low pungency, LD onions are planted in the conventionalway and onions are grown to maturity, harvested, and maintained underlong-term storage conditions for a period of two to six months. Lowpungency onions are thereafter removed from storage and provided duringthe winter to the consumer as a sweet onion.

Although the foregoing invention has been described in some detail byway of illustration and example for purposes of clarity andunderstanding, it will be obvious that certain changes and modificationsmay be practiced within the scope of the invention, as limited only bythe scope of the appended claims. All references cited herein are herebyexpressly incorporated herein by reference.

1.-72. (canceled)
 73. A plurality of onion plants, or parts thereof,wherein said plurality of onion plants are of a Spanish variety thatrequires 14 or more contiguous hours of daylight to initiate bulbformation, wherein said plurality of onion plants are characterized asproducing bulbs having low pungency, said low pungency is measured by anaverage pyruvic acid development (PAD) value less than 5.5 μmol pyruvicacid/gram fresh weight (μmol/g FW pyruvate) at harvest, wherein saidplurality of onion plants produce bulbs which have an average PAD valuethat increases no more than 20% after storage for two months at 5degrees centigrade and 50% relative humidity, wherein said plurality ofonion plants are grown from a seed obtained by crossing a first onionplant selected from the group consisting of WYL 77-5128B having seeddeposited as NCIMB Accession No. 41329, WYL 77-5168B having seeddeposited as NCIMB Accession No. 41330, WYL 77-5128B that possesses amale sterility trait, WYL 77-5168B that possesses a male sterilitytrait, with a second onion plant selected from the group consisting ofcommercial cultivars Daytona, Ranchero, Granero, Sabroso, Tamara,Hamlet, Fortress, Norstar, Teton, Vaquero, Bravo, Regiment, Riviera,Seville, Tesoro, Tribute, Valiant, Vantage, Vega, Viper, Vision, andMira.
 74. The plurality of onion plants, or parts thereof, of claim 73,wherein said low pungency is measured by an average PAD measurement ofless than 5.0 μmol/g FW pyruvate at harvest.
 75. The plurality of onionplants, or parts thereof, of claim 73, wherein said variety producesbulbs that maintain low pungency after storage for a period of about 4months.
 76. The plurality of onion plants, or parts thereof, of claim73, wherein said variety is further characterized as producing bulbswhich have an average PAD value that increases no more than 15% afterstorage for two months at 5 degrees centigrade and 50% relativehumidity.
 77. The plurality onion plants, or parts thereof, of claim 73,wherein said plurality of onion plants are cytoplasmically male sterile.78. The plurality of onion parts of claim 73, wherein said parts areselected from the group consisting of a plurality of seeds, bulbs,leaves, pollen, protoplasts, ovules, and cells.
 79. A tissue culture ofcells obtained from an onion plant of the plurality of onion plants ofclaim
 73. 80. A container of onion bulbs obtained from a population ofthe plurality of onion plants of claim 73, wherein said bulbs comprisean average PAD value of less than 5.5 μmol/g FW pyruvate at harvest andare characterized by a lack of an average PAD value increase of morethan 20% after storage for two months at 5 degrees centigrade and 50%relative humidity.
 81. The container of onion bulbs of claim 80, whereinsaid bulbs comprise an average PAD measurement of less than 5.0 μmol/gFW pyruvate.
 82. The container of onion bulbs of claim 80, wherein atleast 75% of said onion bulbs have a PAD measurement of less than 5.0μmol/g FW pyruvate.
 83. A container of seeds obtained from the pluralityof onion plants of claim 73, wherein said seeds are capable of producingbulbs having an average PAD value of less than 5.5 μmol/g FW pyruvate atharvest, wherein said bulbs are characterized by a lack of an averagePAD value increase of more than 20% after storage for two months at 5degrees centigrade and 50% relative humidity.
 84. The container of seedsof claim 83, wherein onion bulbs from greater than 50% of said seeds arelow pungency onions and wherein a population of onion bulbs grown fromsaid seeds contain an average PAD measurement of less than 5.0 μmol/g FWpyruvate.
 85. The plurality of onion plants, or parts thereof, of claim73, wherein said low pungency is measured by an average PAD measurementof less than 4.5 μmol/g FW pyruvate at harvest.
 86. The plurality ofonion plants, or parts thereof, of claim 73, wherein said low pungencyis measured by an average PAD measurement of less than 4.0 μmol/g FWpyruvate at harvest.
 87. The plurality of onion plants, or partsthereof, of claim 73, wherein said low pungency is measured by anaverage PAD measurement of less than 3.75 μmol/g FW pyruvate at harvest.88. The plurality of onion plants, or parts thereof, of claim 73,wherein said variety produces bulbs that maintain low pungency afterstorage for a period of about 6 months.
 89. The container of onion bulbsof claim 80, wherein said bulbs comprise an average PAD measurement ofless than 4.5 μmol/g FW pyruvate.
 90. The container of onion bulbs ofclaim 80, wherein said bulbs comprise an average PAD measurement of lessthan 4.0 μmol/g FW pyruvate.
 91. The container of onion bulbs of claim80, wherein said bulbs comprise an average PAD measurement of less than3.75 μmol/g FW pyruvate.
 92. The container of seeds of claim 83, whereinonion bulbs grown from greater than 50% of said seeds are low pungencyonions and wherein a population of onion bulbs from said seeds containan average PAD measurement of less than 4.5 μmol/g FW pyruvate.
 93. Thecontainer of seeds of claim 83, wherein onion bulbs grown from greaterthan 50% of said seeds are low pungency onions and wherein a populationof onion bulbs from said seeds contain an average PAD measurement ofless than 4.0 μmol/g FW pyruvate.
 94. The container of seeds of claim83, wherein onion bulbs grown from greater than 50% of said seeds arelow pungency onions and wherein a population of onion bulbs from saidseeds contain an average PAD measurement of less than 3.75 μmol/g FWpyruvate.
 95. The plurality of onion plants, or parts thereof, of claim73, wherein said variety produces bulbs that have an average PADmeasurement of less than 4.75 μmol/g FW pyruvate at harvest.
 96. Apopulation of the plurality of onion plants of claim 73, wherein saidpopulation contains 10, 15, 20, 25, 30, 35, 40, 45, 50, or more onionplants.
 97. The population of onion plants of claim 96, wherein saidonion plants are planted by direct seeding in a field.
 98. The pluralityof onion plants, or parts thereof, of claim 73, wherein said lowpungency further comprises at least a 10% reduction of organosulfurcompounds selected from the group consisting of 1-propenyl cysteinesulfoxide, methyl-cysteine sulfoxide, propyl cysteine sulfoxide, andcombinations thereof.
 99. The plurality of onion plants, or partsthereof, of claim 73, wherein said plurality of onion plants, or partsthereof, are an inbred line.
 100. The plurality of onion plants, orparts thereof, of claim 73, wherein said plurality of onion plants, orparts thereof, are a hybrid line.
 101. The plurality of onion plants ofclaim 73, wherein said crossing further comprises one or more backcrosses of said first onion plant.
 102. The plurality of onion plants ofclaim 73, wherein said crossing further comprises one or morebackcrosses of said second onion plant.